Insulated weather-resistant interlocking roof system and method

ABSTRACT

A roofing system has individual roofing panels that include a metal outer skin surrounding an insulation layer, a factory-applied protective membrane of polyisobutylene, and interlocking components for providing a rigid roof that is self-supporting and requires no sub-deck. The panels with pre-applied protective membranes are adapted to be factory-shipped to a job site so that assembly and sealing can be achieved in a one-step process.

TECHNICAL FIELD

[0001] The present invention relates generally to interlocking,pre-fabricated structural panel systems and, more particularly, to asystem of insulated, weather-resistant interlocking roof panels andassociated methods of use and manufacture.

BACKGROUND OF THE INVENTION

[0002] In roof construction, particularly of the type associated withlarge commercial or industrial buildings, conventional roofing systemsinvolve at least three distinct steps. First, a steel erector willinstall a metal deck which is welded down or screwed down to structuralmembers such as bar joists or purlins. A roofing contractor will theninstall an insulation layer, which typically comprises a three-inchlayer of polyurethane. In the final step, the roofing contractor willinstall a weather-resistant, corrosion-resistant membrane over theinsulation layer in order to seal the roof assembly.

[0003] Construction time and costs, and structural weight, can beconsiderably reduced by eliminating one or more of the above-mentionedsteps. Various designs exist for modular, pre-fabricated roofing panelsthat eliminate the separate steps of installing a metal roof deck andinstalling an insulation layer. One such design is disclosed in U.S.Pat. No. 5,277,011, in which pre-fabricated roofing panels comprisingmetal outer skins and an insulating filler material are directly securedto transverse purlins, thereby eliminating the need for a separate basedeck and associated procedural steps. The roofing panels require,however, weather strips or sealing joints, as well as water-drainagechannels.

[0004] Another type of roofing panel is disclosed in U.S. Pat. No.4,575,981. The panel, which is designed for use in an inclined roof,comprises a metal outer sheet over a foam or plastic core and has on oneside a male or female component, respectively, of a ship-lapped jointdesigned for interlocking. The ship-lapped joint requires the use of asealant rod or caulk strip for forming a water-tight seal and isdesigned for uni-directional primary sealing and, thus, is suitable onlyfor inclined roofs in which the joints are uni-directionally aligned.

[0005] U.S. Pat. No. 5,394,672 discloses a roof panel system in whichpanels comprise outer metal sheets surrounding an insulation core andhaving alternate mating edges for interlocking adjacently placed panels.The panels disclosed in this patent, as well as those described in U.S.Pat. No. 4,578,981 and U.S. Pat. No. 5,277,011, are not provided withpre-applied corrosion-resistant membranes. The panels described in U.S.Pat. No. 5,394,672 require an additional step of applying awater-resistant polymeric paint after the roof is assembled.

[0006] U.S. Pat. No. 4,706,435 describes a roof panel comprising a fiberboard panel having a factory-installed, bitumenized waterproof membrane.The membrane is arranged to provide one head-lap and one side-lap sothat lap joints can be achieved between adjacently placed panels. Thelaps, however, require the additional step of spot-mopping hot asphaltor adhesive along the side-lap or head-lap during installation. Thepanels are designed to be installed on a substrate or pre-existing deckand are not capable of forming, by themselves, a structurally sufficientroof.

OBJECTS OF THE INVENTION

[0007] It is an object of the present invention to provide a roofingsystem comprising pre-fabricated roofing panels of a design that affordsstructural strength, that eliminates the need for a roof sub-deck, thatprovides superior insulation and corrosion-resistance, and thatsignificantly simplifies manufacturing and assembly methods and reducesassociated costs. By eliminating the need for a sub-deck and additionalsealing materials, overall weight and cost of materials are reduced.Simplification of roof assembly reduces labor costs and assembly time.

[0008] It is another object of the invention to provide a method ofmanufacturing such panels in which an outer, protective layer is appliedto the panels in a continuous process so that the panels can be shippedto a job site with the protective layer pre-installed allowing forone-step roof assembly and sealing.

[0009] These and other objects of the invention are inherently disclosedin the description that follows.

SUMMARY OF THE INVENTION

[0010] A preferred embodiment of the present invention is directed to aroofing system comprising individual roofing panels that include a metalouter skin surrounding an insulation layer, a factory-applied protectivemembrane, and interlocking components for providing a rigid roof that isself-supporting and requires no sub-deck. The panels with pre-appliedprotective membranes are adapted to be factory-shipped to a job site sothat assembly and sealing can be achieved in a one-step process. In thepreferred embodiment, upper and lower steel skins are rolled out andmaintained at a desired distance while foam insulation is injectedtherebetween. A corrosion-resistant membrane of polyisobutylene isrolled out and applied to the outer surface of the upper steel skinusing a spray adhesive. Along the longitudinal edges are matingconfigurations designed to interlock adjacently placed, like panels.Reinforcing strips and screw holes are provided for enhanced strengthand fastening capabilities.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1A is a schematic, perspective view of a panel according to apreferred embodiment of the invention.

[0012]FIG. 1B is a schematic, cross-sectional end view of the panel ofFIG. 1A taken along line I-I.

[0013]FIG. 2A is a schematic, cross-sectional, partial end view of twopanels of the type shown in FIG. 1B adjacently positioned andinterlocked according to the present invention.

[0014]FIG. 2B is a schematic, perspective view of two panels of the typeshown in FIG. 1A adjacently positioned, interlocked and mounted tostructural members according to the present invention.

[0015]FIG. 3 is a schematic, partial cross-sectional side view of twopanels of the type shown in FIG. 1A placed end-to-end and mounted to astructural member according to the present invention.

[0016] FIGS. 4A-4B are schematic diagrams of a manufacturing system andmethod for making a panel of the type shown in FIG. 1A according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A building panel (110) according to a preferred embodiment of thepresent invention is shown in FIGS. 1A and 1B. The panel (110), whilepresented herein for use as a roof panel, may be utilized for otherpurposes in which similar or analogous environmental and structuralconditions exist. The panel (110) includes an upper membrane (112), alower membrane (114), an interior section (116), and a protective outermembrane (118).

[0018] The upper and lower membranes (112, 114) are made from steelsheets and may be made from other suitable metallic or non-metallicmaterials having similar properties. In the preferred embodiment, 22-26gauge steel is used for the membranes (112, 114).

[0019] The interior section (116) serves primarily as an insulationlayer. Depending on the desired use, the interior section may beenhanced for additional purposes such as fire-resistance or strengthenhancement. In the preferred embodiment, the interior section (116) iscomprised of a three-inch layer of polyurethane foam. If desired, theinterior section (116) may comprise multiple layers of differentmaterials having various characteristics suitable for the panel'sintended use.

[0020] The outer membrane (118), which is designed to withstand thecorrosive effects of weathering, is comprised of a membrane ofpolyisobutylene (PIB), such as that available in single-ply sheets fromRepublic Powdered Metals, Inc. and sold under the mark “GEOFLEX HD.” Theouter membrane (118) is adhered to the upper membrane (114).

[0021] Referring to the cross-sectional view of FIG. 1B of the panel(110), the upper and lower membranes (112, 114) are arranged generallyin parallel relationship. They are off-set vertically and horizontallyto accommodate the angled side walls (120, 122) of the interior section(116) which, as described below, are configured to provide lock-fittedmating between adjacent panels.

[0022] As shown in FIG. 1B, the outer membrane (118) is provided with aside-lap portion (124) that extends beyond a lateral edge of the panel(110). The side-lap (124) may extend any suitable distance to form awatertight, weatherproof seal between adjacently engaged panels, asdescribed in more detail below. In the preferred embodiment, theside-lap extends approximately 4 inches. An end-lap (126) may beprovided on a first end (142) of the panel (110) to provide a watertightseal between adjacent panels placed end-to-end. The underside (125) ofthe lap portions (124, 126) is provided with a peel-away sheet (127)having adhesive (129) underlying which, when peeled away, facilitatesadhesion of the laps (124, 126) to adjacently placed panels (110).

[0023] A first side wall (120) extends downwardly from a first edge ofthe upper membrane (112) at an angle β to the edge of the upper membrane(112). In the preferred embodiment, the angle β is approximately 45°though this angle may be varied. A first male connecting member (130)extends outwardly from the first sidewall (120) in a horizontaldirection. A first female connecting member (132) is positioned belowthe male member (130) and extends inwardly from the first sidewall (120)in a horizontal direction.

[0024] Opposite the first sidewall (120) is a generally parallel secondsidewall (122) that extends between the upper and lower membranes (112,114). The second sidewall (122) has second male and female connectors(136, 138) that are positioned opposite the first male and femaleconnectors (130, 132) with respect to vertical position in order toalign in mating relationship when like panels (110) are engagedadjacently, as shown in FIG. 2A. Reinforcing members (140, 142) areprovided in the form of steel, elongated strips that add strengthreinforcement to the connectors (132, 138). Additional reinforcingmembers may be provided to remaining connectors or other sections of thepanels.

[0025] As shown in FIGS. 2A-2B, the panels (110) are assembledadjacently such that they each span, in a longitudinal direction,consecutive structural members (144, 146) such as joists or purlins. Foreach distance L between consecutive structural members (144, 146) eachpanel (110) should be at least L in length.

[0026] Referring to FIGS. 2A and 2B, each panel (110) may be providedwith a first screw hole (148) adapted to receive a screw (152) forsecuring the panel (110) directly to a flange (154) of a structuralmember (144). Each panel (110) also may include second and third screwholes (156, 158) through male and female connectors (136, 132). Theholes (156, 158) line up, respectively, when adjacent panels (110) areengaged as shown in FIG. 2A, providing a passage for a second screw(160) which locks adjacent panels (110) to each other and, if desired,to the flange (154) of the structural member (144).

[0027] Each panel (110) may be selected to be of a length suitable forits purpose without the need to be placed end-to-end with another panel(110). Alternatively, the panels (110) can be placed end-to-end inaddition to being placed adjacently side-by-side as described withrespect to FIGS. 2A-2B. For example, as shown in FIG. 3, panels (110)placed end-to-end may be positioned so that a first end (162), having anend-lap (163) as shown in FIG. 1A, can be placed next to another panel'ssecond end (164) having no lap. The connection can be positioneddirectly above a structural member (166) thereby providing support and asurface (168) for securing a plurality of screws (170) to hold thepanels (110) to the structural member (166).

[0028] Because the panels (110) are factory-shipped with the outermembrane (118) pre-applied and adapted to form sealed joints, theassembly and sealing of a roof section using the panels (110) isachieved in one step.

[0029] The panels (110) according to the present invention aremanufactured according to a preferred method described herein. Referringto FIG. 4, a schematic representation depicts first and second steelmembrane rolls (200, 202) of pre-selected widths corresponding to apredetermined panel width. The rolls (200, 202) have associated drivers(204, 206) of the type generally known in the art. One or morecontollers (208) of the type known in the art may be associated witheach driver to control various functions. The drivers (204, 206) areactivated to selectively unroll the steel membranes (210, 212) whichform the upper and lower membranes (112, 114) of the finished panels(110) according to the present invention. Tension rollers (214) orsimilar means are employed to maintain the membranes (210, 212) at aconstant distance to hold them generally parallel to each other as theyare unrolled.

[0030] The reinforcing members (140, 142) may be formed by bending alateral edge of the steel membranes (210, 212) or by welding orotherwise fastening the reinforcing members (140, 142) to the steelmembranes (210, 212). In the preferred embodiment, the reinforcingmembers (140, 142) are conveyor-fed from rolls (141, 143) insynchronization with the feeding of the steel membrane rolls (200, 202).The reinforcing members may be held in position by injected foam, asdescribed below, or adhered, by conventional means, directly to thesteel members (210, 212). As the steel membrane rolls (200, 202) unrollthe steel membrane (212, 214), an injection device (216), or pluralitythereof of a conventional type, injects polyurethane foam between thesteel membranes (212, 214) to form the interior section (116) of thepanel (110). Conventional molding plates (213, 215) or similar means asare known in the relevant art are selectively positioned duringinjection of the foam to shape the angled sidewalls with male and femaleconnectors as described above, or additional features. A final step ofapplying the outer membrane (118) to the upper membrane (114) is carriedout after cutting off the panels (110) to desired lengths. Aconventional cutter (217) cuts off the panel (110) at a desired length.

[0031] Referring to FIG. 4, panels (110), having been cut but not yethaving the outer membrane applied are conveyed past a first limit switch(230). The first limit switch (230) is tripped to activate a first aircylinder (232). The first air cylinder (232) moves two side rollers(234, 236) into engagement with the panels (110) to bias the panels(110) against oppositely mounted idler rollers (238, 240) to align thepanels (110). The side rollers (234, 236) are driven by a variable speedmotor system (242, 244) which advances the panels (110) along at a speedin the range of one to sixty feet per minute in a direction representedby the arrow (231) shown in FIGS. 4A-4B.

[0032] As each panel (110) advances, it trips a second limit switch(246) which activates two spray guns (248, 250) that spray caulk on eachside of the panel (110) into the female connectors (132, 138) to enhancefit and sealing between adjacently mated panels (110).

[0033] Referring to FIGS. 4A-4B, each panel (110) will continue to movealong until it trips a third limit switch (252). The third limit switch(252) activates adhesive spray guns (254, 256) which spray adhesive ontothe upper membrane (114).

[0034] Each panel (110), with adhesive applied, advances while the PIBmembrane (217) is unrolled and applied to the adhesive-treated area ofthe panel (110). In applying the outer membrane (118), comprising a PIBmembrane, the outer membrane material is provided in as large a roll(217) as possible for optimal production efficiency. The PIB roll (217)is mounted to a roller driver assembly (218) of the type generallyknown. The PIB roll (217) is positioned and introduced from above theproduction line for the panels (110) after they have been cut. Bypositioning and running the PIB roll (217) above the panel productionline, selective positioning of the PIB roll for proper alignmentrelative to the panels to be formed is achieved. As the PIB membrane(217) is unrolled it travels through a conventional pinch roll system(220), down a slide (222) and under a pressure roller (224). When onePIB roll (217) runs out of material, an operator will bond the end ofthe material with that of a new roll to maintain continuity in theoperation. One or more rollers such as pressure roller (258) presses thePIB membrane (217) against the panel upper membrane (114) therebycausing adhesion therebetween. The pressure roller (258) can be mountedto an air cylinder (260) or other conventional means to activate thepressure roller (258) in response to tripping of a fourth limit switch(262) by the advancing panel (110). The fourth limit switch (262) alsoactivates a flying cutter (266) of a conventional type that cuts the PIBmembrane (217) at both leading and trailing ends. In the preferredembodiment, the end lap (163) is formed at the trailing end. Byadjusting the fourth limit switch (262), the length of the end-lap (163)can be varied. In the preferred embodiment, the end-lap (163) extends 1to 4 inches. Similarly, as the trailing end (264) of each panel (110)passes each of the limit switches described above, each associatedoperation is stopped as re-set for the next passing panel. The siderollers (234, 236) will continue to run thereby advancing each panel(110) on to further operations such as stacking, banding and shipping.

[0035] While the preferred embodiments of the present invention havebeen herein describd, it is understood and acknowledged that variousmodifications can be made without departing from the scope of thepresent invention. For example, the novel method described and claimedherein for factory-applying an outer sealing membrane to apre-fabricated roof panel may be carried out with panels that vary fromthe precise configuration described above with respect to the preferredembodiment. Similarly, the novel method described and claimed herein forassembling and seating a roof system in a single process step may becarried out with panels that vary from the precise configurationdescribed above with respect to the preferred embodiment.

What is claimed is:
 1. A structural roof panel comprising an uppermembrane having a generally rectangular shape; a lower membrane having asimilar shape as, and being positioned below and generally parallel to,said upper membrane, an intermediate section between said upper andlower membranes; and an outer membrane fixed to the upper surface ofsaid upper membrane.
 2. A panel according to claim 1, wherein said outermembrane comprises polyisobutylene.
 3. A panel according to claim 1,wherein said upper and lower membranes comprise steel sheets; and saidintermediate section comprises polyurethane foam.
 4. A panel accordingto claim 1, further comprising a first male tongue and a first femalegroove running along and generally parallel to a first sidewall of saidpanel; and a second male tongue and a second female groove running alongand generally parallel to a second sidewall of said panel, said secondsidewall being opposite to and generally parallel to said firstsidewall; and said first and second tongues and grooves being adapted tolockingly engage, respectively, with corresponding tongues and grooveson similar panels placed adjacently to said roof panel.
 5. A panelaccording to claim 4, further comprising a first and second steel liningmember associated with and lining each of said first and second femalegrooves, respectively.
 6. A panel according to claim 4, wherein saidfirst and second sidewalls are angularly offset with respect to saidupper membrane by a first angle.
 7. A panel according to claim 6,wherein said first angle is in the range of approximately 0 degrees to45 degrees.
 8. A panel according to claim 6, wherein said first angle isapproximately 45 degrees.
 9. A panel according to claim 4, wherein saidfirst male tongue is positioned above said first female groove, and saidsecond female groove is positioned above said second male tongue.
 10. Apanel according to claim 4, wherein said outer membrane comprisespolyisobutylene.
 11. A panel according to claim 4, further comprisingattaching means for attaching said panel to a structure upon which saidpanel is positioned, said attaching means comprising a screw hole insaid panel extending from said lower membrane and into said intermediatesection and being adapted to receive a screw therein.
 12. A panelaccording to claim 1, wherein said outer membrane extends beyond atleast one edge of said upper membrane so as to form a lap section foroverlapping a joint between said roof panel and an adjacently placed,like panel.
 13. A panel according to claim 12, further comprisingadhesive fixed to the underside of said lap section for adhering to saidadjacently placed, like panel; and a peel-away sheet covering saidadhesive and being selectively removable to expose said adhesive.
 14. Aroofing system for assembling a roof directly upon a series of generallyparallel, laterally-spaced elongated structural support members, saidsystem comprising a series of generally rectangular panels each adaptedto span at least the length of the distance between a successive pair ofsaid structural support members; each said panel comprising a first maletongue and a first female groove on one sidewall, and a second maletongue and a second female groove on an opposite sidewall, therebyadapting each panel to be adjacently positioned and interlocked withanother panel by mating of said first and second male tongues with saidfirst and second female grooves; and each said panel comprising amembrane of polyisobutylene fixed to the top surface of each panel. 15.A roofing system according to claim 14, wherein each said panel furthercomprises a lap portion of said polyisobutylene membrane that extendsbeyond at least one side of said panel, said lap portion being adaptedto overlap a joint between an adjacently placed panels.
 16. A roofingsystem according to claim 15, wherein said lap portion is provided withadhesive fixed to the underside of said lap portion for adhering to saidadjacently placed panels.
 17. A roofing system according to claim 16,further comprising a peel-away sheet covering said adhesive and beingselectively removable to expose said adhesive.
 18. A roofing systemaccording to claim 14, wherein each panel comprises an upper and lowersteel membrane, each being generally parallel to the other; and anintermediate portion between said upper and lower steel membranes.
 19. Aroofing system according to claim 18, wherein said one sidewall and saidopposite sidewall are each angularly offset with respect to said uppermembrane at an angle in the range of about 0 degrees to 45 degrees. 20.A roofing system according to claim 18, wherein said one sidewall andsaid opposite sidewall are each angularly offset with respect to saidupper membrane at an angle of about 45 degrees.
 21. A roofing systemaccording to claim 14, wherein each panel comprises attaching means forattaching said panel to said structural support members, said attachingmeans comprising a screw hole in said panel extending from said lowermembrane and into said intermediate section and being adapted to receivea screw therein.
 22. A method of making a structural roof panel, saidmethod comprising providing an upper membrane; providing a lowermembrane, providing an intermediate layer between said upper and lowermembranes; and adhering to said upper membrane an outer membrane ofpolyisobutylene.
 23. A method according to claim 22, wherein said upperand lower membranes are provided on rolls which are controllablyunrolled generally simultaneously, while said upper and lower membranesare maintained in spaced apart, generally parallel relationship; saidouter membrane is provided on a roll which is positioned above saidupper membrane and controllably unrolled; an adhesive is applied betweensaid upper membrane and said outer membrane; and a pressure rollerbiases said outer membrane against said upper membrane to facilitateadhesion therebetween.
 24. A method according to claim 23, wherein priorto the step of applying adhesive, a first cutter cuts off said upper andlower membranes, and said intermediate layer, thereby forming agenerally rectangular panel; and subsequent to biasing said outermembrane against said upper membrane, a second cutter cuts off saidouter membrane at a desired length relative to said panel.
 25. A methodaccording to claim 24, wherein said desired length to which said outermembrane is cut is longer than the length of said panel.
 26. A methodaccording to claim 22, wherein said panel includes opposed sidewallsextending between said upper membrane and said lower membrane, eachsidewall being formed with a male tongue and a female groove adapted tomate in interlocking fashion with like tongues and grooves onadjacently-placed, like panels.
 27. A method according to claim 22,wherein said method is a single, continuous process.
 28. A method ofassembling a roof structure, said method comprising providing aplurality of roof panels each having a pre-applied, weather-resistantouter layer; placing said roof panels adjacently with respect to eachother; and structurally attaching said panels to each other.
 29. Amethod according to claim 28, further comprising overlapping at least aportion of one of said panels with respect to an adjacently placed panelthereby forming a weatherproof, water-tight sealed joint.
 30. A methodaccording to claim 28, wherein said outer layer comprises a membrane ofpolyisobutylene.
 31. A method according to claim 29, wherein an adhesiveis pre-applied to the underside of said portion.